The enzyme-linked immunosorbent assay (ELISA) is being developed to detect class specific antibody to various parasitic diseases as well as circulating antigen to Toxoplasma. An epidemic of ovine abortion has been observed on a farm in Virginia which produces sheep for NIH research. Serological studies indicate Toxoplasma as the cause of the abortions. All five cats living on the farm had high hemagglutination (IHA) titers for toxoplasma antibody. The IHA test for Sarcocystis previously developed in this Laboratory was used in the diagnosis of the first confirmed outbreak of bovine Sarcocystis in the U.S. BIBLIOGRAPHIC REFERENCES: Lunde, M.N. and Fayer, R.: Serologic tests for antibody to Sarcocystis in cattle. J. Parasitol. 63: 222-225, 1977. Fayer, R., and Lunde, M.N.: Changes in serum and plasma proteins and in IgG and IgM antibodies in calves experimentally infected with sarcocystis from dogs. J. Parasitol. 63: 438-442, 1977.